A couple of repitching questions

[roddog]

Hello,

I did a 70-shilling Scottish ale on chico yeast and have racked off all but the last 1.5 inches from the primary a week ago. So the cake has been continuously under beer since then and have been in the garage in the upper 50's this past week. I'm doing a IIPA and going to repitch this yeast. A few questions:

1. As long as the yeast has been under beer this past week it should have no net negative effects, right?
2. The previous brew was a 1.038 and this one is in the 1.070ish range. I see that there is no need to oxygenate, but is there also not a need to add yeast nutrient? That is mostly for growth right?

Cool, thanks for the input.

R

 

[hotwatermusic]

No expert, but when I've used nutrient it was because it was an extract based starter, and yes it was mostly to help build a bigger count of healthy yeast. Think you should have a proper count and since you're taking off a 38er they shouldn't be stressed, and ready to work.

 

[hannibalmdq]

What makes you say there is no need to oxygenate? Unless you are providing the lipids and sterols required to maintain cell wall flexibility from some other source I think you should plan on providing oxygenation, especially when considering the OG of your planned brew.

Oh, and the yeast was fine stored at 50ish under beer.

 

[Calder]

Check to make sure your 1.5 inches of beer has not started to turn into vinegar. If it hasn't, just drain off and pitch on the cake. If it has, then you need to wash the yeast.

Going from a 1.038 to a 1.070, you will be slightly over-pitching using a full cake, but that may be offset by having keept the yeast at 50 F for a week (you probably lost some yeast). You might be close to the perfect pitch. Pitching the right amount of yeast means that you do need to aerate the wort. The yeast need the O2 to reproduce and build their colony.

No nutrient needed. Most malt worts have plenty of nutrient. Also dead yeast cells (and you have a lot) is nutrient for the live yeast. Yes, they are cannibals.

 

[flars]

Use Mrmalty to determine how many milliliters of yeast you will need to pitch. Pour the contents of the fermentor into two quart mason jars to help determine how much yeast you have.
The entire cake would be and over pitch. With a large over pitch you won't get the new cell growth needed before the available oxygen is depleted. Aerate very well.

 

[Calder]

Use Mrmalty to determine how many milliliters of yeast you will need to pitch. Pour the contents of the fermentor into two quart mason jars to help determine how much yeast you have.
The entire cake would be and over pitch. With a large over pitch you won't get the new cell growth needed before the available oxygen is depleted. Aerate very well.

He is going 2X the gravity for the new beer (so needs 2X the yeast). When do you dial in the date for Mr. Malty (which I have issues with anyway). I think he is over-pitching, but not too much. If the gravity were the same, I would have the same concerns.

I have lots of mason jars of slurry, and there is no-way I can assess how much yeast or trub I have in any of them.

 

[dinnerstick]

leaving the beer and yeast open to so much air is not great practice, generally you want to get your yeast harvested and away from oxygen as quickly as is practical. a small head space in the top of a jar is one thing, and essentially unavoidable, but a whole 20L or whatever worth of ambient air for a week is another.

 

[WoodlandBrew]

Here is some data showing yeast viability as a function of alcohol exposure.

http://www.woodlandbrew.com/2013/01/abv-effects-on-yeast.html

 

[roddog]

Thanks for all the advice, I followed Mr malty, and a little more. Took off Luke a rocket and actually blew the top off the brew bucket. Mess inside the fermenting chamber... Chugging along nicely though.